Show regular Colin Murray will take Nick's place for the duration of lockdown.
Taking to Twitter, Nick said: "Good luck to Colin Murray, popular dictionary corner guest and Countdown fanatic, who takes over from me as host today and for the rest of Covid Lockdown recordings (although I’ll still be on your screens for a week or two) as this 76 year old shields at home - in spite of the amazing military-style safety protocols put in place by ITV Studios and Channel4. Between you and me, I’d have confidently carried on, but the family has handcuffed me to a radiator, saying ‘you’re not going anywhere’. So have fun Colin and keep my chair warm for me."
Countdown continues weekdays at 2:10pm on Channel 4.